Boston Python Workshop 3/Friday/Windows Python scripts: Difference between revisions

We are going to practice writing and running Python scripts.

===Start your text editor===

# Launch the Notepad++ text editor. See the [[Boston Python Workshop 3/Friday/Windows_text_editor|Windows text editor setup]] instructions for the steps to do this.

# Start a new, blank text file.

===Write and save a short Python script===

# Add the following line to your new text file:

<pre>

print "Hello World!"

</pre>

# Save the script as <code>hello.py</code> in your Desktop directory. The <code>.py</code> extension indicates that this file contains Python code.

===Run the script===

# Start a new command prompt. See the [[Boston Python Workshop 3/Friday/Windows terminal navigation|terminal navigation on Windows]] instructions for the steps to do this.

# Navigate to your Desktop directory from a command prompt, using the <code>dir</code> and <code>cd</code> commands. See the [[Boston Python Workshop 3/Friday/Windows terminal navigation|terminal navigation on Windows]] instructions for a refresher on using these commands. Don't hesitate to get help from a staff member on this step if you need it -- it's a new way of navigating your computer, so it may be unintuitive at first!

# Once you are in your Desktop directory, you'll see <code>hello.py</code> in the output of <code>dir</code>.

# Type

<pre>

python hello.py

</pre>

and hit enter. Doing this will cause Python to execute the contents of that script -- it should print "Hello World!" to the screen. What you've done here is run the Python application with an argument -- the name of a file, in this case "hello.py". Python knows that when you give it a file name as an argument, it should execute the contents of the provided file. You get the same result as if you typed

<pre>

print "Hello World"

</pre>

at a Python prompt and hit enter.

===Success===

You created and ran your first Python script!

* When you run the <code>python</code> command by itself, you start a Python prompt. You can execute Python code interactively at that prompt.

* When you run the <code>python</code> command with a file name as an argument, Python executes the Python code in that file.

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